On paper, that is sufficient for low to moderate use. I've seen reports on this forum about speeds dropping with IPS, but not the degradation that will lose ping packets. What latency are you seeing to 8.8.8.8?

I'm not familiar with Proxmox or Hetzner but it may be fixable with PCI pass-through NIC's rather than using the (para) virtualised interfaces. This also depends on your throughput, to decide if it is worthwhile.